Wrapper to implement Bootstrap 2.0 style form element rendering.
This wrapper does some very specific Bootstrap things,
like wrap the form elements in divs with non-changeable classes.
It is not as flexible as the 'Simple' wrapper,
but means that you don't have to specify those classes in your form code.

It wraps form elements with 'control-group' divs,
and form 'actions' with 'form-actions' divs.
It adds special additional wrappers for checkboxes and radio buttons,
with wrapped labels.